Spinal injection of pain-relieving medicine is very effective. Since the duration of the pain relief is limited, an epidural catheter is usually placed at the same time to be used later. Epidural catheters can be misplaced and must be tested for location before medicine can be administered. The best method for testing catheter location has not been determined. The purpose of this study is to determine if a commonly used epidural test dose can effectively distinguish between a spinal and an epidural catheter after a spinal epidural.